INTRODUCTIONWe developed a new imaging system (HyperEye Medical System, HEMS) for simultaneously capturing near-infrared (NIR) fluorescence of indocyanine green (ICG) and visible light through a unique, high-sensitive, charge-coupled device (CCD) area sensor coated with arrays of red-, green-, blue-, and NIR-specific filters. Unlike multiple-sensor systems, HEMS enables real-time color-NIR imaging in ICG fluorescence-guided endoscopic surgery without the need for special video data laparoscope processing to superimpose the NIR signal on color images. We have developed a prototype that captures NIR fluorescence of ICG (HEMS-E) and carried out preliminary evaluation of the system in laparoscopic colon surgery.

METHODS AND PROCEDURETo label a site of interest, we injected 0.2 ml of ICG solution (1 mg/ml) and 0.2 ml of Indian ink into the submucosal layer adjacent to the tumor to be resected.While ICG was excited with a custom-made xeon fiber illumination system, NIR fluorescence and color images were visualized with HEMS through the NIR-compatible endoscope.

RESULTSThe resolution of our new endoscopic imaging is still insufficient for surgical procedures. However, our new HEMS-E imaging system could detect the fluorescence of ICG even in cases where the Indian ink was not visible by conventional laparoscopy (HD Endoeye LTF-VHTM, Olympus, Japan).

CONCLUSIONSThe resolution of HEMS-E should be improved to satisfy the needs of lararoscopic surgery using this system. However, the detection limits for tumor sites during laparoscopic surgery by HEMS-E is superior to that provided by a standard laparoscope using Indian ink. Further development of HEMS-E is going to meet the needs of the surgeon.